Device and method for facilitating hemostasis of a biopsy tract

ABSTRACT

A system including an adaptor and a syringe is used for facilitating hemostasis of a biopsy tract or other puncture wound by delivery of an absorbable sponge in a hydrated state into the wound. The adaptor includes a tapered lumen for hydrating and compressing the relatively large absorbable sponge for delivery through a relatively small cannula, such as a biopsy needle. The hydrated absorbable sponge is injected through the biopsy needle into the biopsy tract by fluid. Alternatively, the sponge may be delivered to the biopsy needle by injection of fluid and then delivered to the biopsy tract by a plunger or stylet. The implanted absorbable sponge facilitates hemostasis at the biopsy site or other puncture wound and minimizes the chance of internal bleeding. The absorbable sponge material is absorbed by the body over time.

This application is a continuation of U.S. application Ser. No.09/613,059, filed on Jul. 10, 2000 which is a continuation of 09/247,880filed on Feb. 10, 1999, which is a continuation-in-part of 09/071,670,filed May 1, 1998.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a wound closure device, and more particularly,the invention relates to a device and method for facilitating hemostasisof a biopsy tract or other puncture wound by injection of an absorbablesponge.

2. Brief Description of the Related Art

Percutaneous needle biopsy of solid organs is one of the most commoninterventional medical procedures. Millions of percutaneous needlebiopsies are performed annually in the United States and throughout theworld. Percutaneous biopsy is a safe procedure which has supplantedsurgical biopsy for many indications, such as skin biopsy and liverbiopsy.

Possible complications of needle biopsy include bleeding at the biopsysite. The amount of bleeding is related to a number of factors includingneedle size, tissue sample size, patient's coagulation status, and thelocation of the biopsy site. Vascular organs such as the liver, a commonbiopsy target, may bleed significantly after needle biopsy. To minimizebleeding from a biopsy site, small-gauge needles are typically used.Small gauge needles, however, produce less satisfactory biopsy specimensbut frequently are favored over larger bored needles because of theirperceived safety. In order to minimize the chance of internal bleedingafter biopsy, external pressure is applied and patients are often askedto lie in uncomfortable positions, such as the lateral decubitusposition, for a number of hours, particularly after liver biopsy.

Sterile sponges, such as Gelfoam, are prepared in dry sterile sheetswhich are used as packing material during surgery for control ofbleeding. The sponge sheets are left in the surgical site after surgeryto stop bleeding and are absorbed by the body in 1 to 6 weeks. A numberof techniques have used these absorbable sterile sponge materials toplug a biopsy tract to minimize or prevent bleeding. The absorbablesponge provides a mechanical blockage of the tract, encourages clotting,and minimizes bleeding though the biopsy tract. Despite the advantagesof using absorbable sponge to plug a biopsy tract this technique has notachieved widespread use because of difficulty in preparing anddelivering the sponge material into the biopsy tract.

One example of a biopsy wound closure device using an implantable spongeis described in U.S. Pat. No. 5,388,588. According to this patent, acircular sponge of an absorbable foam material is precut and insertedinto a biopsy site by an applicator rod having the sponge positioned onthe end. Once the sponge is implanted, the sponge absorbs blood andswells to fill the tract preventing further bleeding at the biopsy site.However, the sponge is difficult to deliver and expands slowly oncedelivered. In addition, this delivery method can only deliver a spongeof a limited size which provides less local compression than desired andmay incompletely fill the target site. Further, bleeding may continuealong sections of the biopsy tract where no sponge has been delivered.

Accordingly, it would be desirable to provide a device and method whichwill permit the delivery of an absorbable sponge to a biopsy tract in asimple and reliable manner.

SUMMARY OF THE INVENTION

The present invention relates to a device and method for facilitatinghemostasis of a biopsy tract or other puncture wound by injecting anabsorbable sponge. The system according to the present invention allowsthe sponge to be delivered in a hydrated state through the biopsy needleor other cannula directly into the puncture wound.

In accordance with one aspect of the present invention, a system forinjecting a sponge into tissue includes a pledget of sponge having aproximal end with a larger cross sectional area than a distal end, acannula for delivering the pledget in a hydrated state to the tissue,and an adaptor connectable to the cannula for hydrating and deliveringthe pledget to the cannula, the adapter having a tapered lumen with alarge diameter proximal end and a small diameter distal end, wherein thesmall diameter distal end is connectable to the cannula.

In accordance with an additional aspect of the present invention, amethod of forming a sponge pledget for delivery to tissue includes stepsof cutting a strip of sponge from a sheet of sponge material and foldingthe strip to form a pledget with a first end having a first crosssectional area and a second folded end having a second cross sectionalarea which is larger than the first cross sectional area.

In accordance with a further aspect of the present invention, a systemfor preparing and delivering a hydrated sponge to a cannula for deliveryto tissue includes an adaptor and a template. The adaptor includes anelongated member having a first end, a second end, and a lumen extendingfrom the first end to the second end, a luer connector provided at thesecond end for connection to a cannula, a tapered section of the lumentapering from a first diameter at the first end to a second diameter atthe second end which is smaller than the first diameter such that a drysponge pledget having a width larger than the second diameter iscompressible when hydrated to allow passage of the pledget into thesecond diameter. The template is configured for use in cutting thesponge to a size to be received in the elongated member for delivery tothe cannula.

In accordance with an additional aspect of the invention, an adaptorsystem for delivering a hydrated sponge to a cannula for delivery totissue includes an elongated adaptor having a distal end, a proximalend, a lumen tapering from a larger diameter at a proximal end to asmaller diameter at the distal end, and a luer connection at the distalend, and a removable vent cap configured to engage the luer connection,the vent cap having a vent hole which allows fluid to pass out of theadaptor through the cap but prevents the sponge from passing through thevent hole.

In accordance with another aspect of the invention, a method ofdelivering a sponge into a tissue access tract includes the steps ofdelivering a hydrated sponge pledget through a cannula positioned in atissue access tract at a velocity E while withdrawing the cannula fromthe tissue at a velocity V to deposit the sponge pledget and seal thetissue access tract, wherein the velocity E is greater than or equal tothe velocity V.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described in greater detail with reference tothe preferred embodiments illustrated in the accompanying drawings, inwhich like elements bear like reference numerals, and wherein:

FIG. 1 is a perspective view of a punch for forming pledgets;

FIG. 2 is a side cross sectional view of an adaptor for delivery of apledget to a needle;

FIG. 3 is a side cross sectional view of a syringe for connection to theadaptor;

FIG. 4 is a side cross sectional view of an adaptor and syringecombination with a pledget positioned within the adaptor;

FIG. 5 is a side cross sectional view of an adaptor and syringecombination in accordance with an alternative embodiment in which thepledget has been hydrated and moved into a small diameter end of theadaptor;

FIG. 6 is a side cross sectional view of the loaded adaptor and syringecombination in preparation for connection to a biopsy needle;

FIG. 7 is a side cross sectional view of an alternative embodiment of anadaptor connected to a biopsy needle and syringe;

FIG. 8 is a side cross sectional view of an alternative embodiment of anadaptor;

FIG. 9 is a side cross sectional view of an alternative embodiment of anadaptor with enlargements in the lumen for kneading the pledget;

FIG. 10 is a side cross sectional view of an alternative embodiment ofan adaptor with irregularities in the lumen for kneading the pledget;

FIG. 11 is a side cross sectional view of an alternative embodiment ofan adaptor for delivery of a pledget including a template attached tothe adaptor;

FIG. 12 is a bottom view of the adaptor and template of FIG. 11;

FIG. 13 is a top view of the template as it is used for cutting apledget from an absorbable sponge sheet;

FIG. 14 is a side cross sectional view of a distal end of an adaptorwith a vent cap attached;

FIG. 15 is a side cross sectional view of the adaptor and vent cap ofFIG. 14 having a pledget staged within the adaptor; and

FIG. 16 is a side cross sectional view of a portion of an organ and asystem for delivering a pledget into a biopsy tract in the organ.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The system of the present invention delivers an absorbable spongematerial in a hydrated state to facilitate hemostasis of a biopsy tractor other puncture wound in a simple and safe manner. The apparatus fordelivering a hydrated absorbable sponge will be described below inconnection with treatment of a biopsy tract after a percutaneous needlebiopsy. However, the invention may be used for facilitating hemostasisof other types of puncture wounds or tissue access tracts to preventbleeding of these wounds.

The system for facilitating hemostasis of the biopsy tract includes apunch 10 for cutting a pledget 18 of absorbable sponge material from asheet of this material, an adaptor 12 for delivering the pledget to abiopsy needle 16, and a syringe 14 for hydrating and injecting thepledget. The adaptor 12 allows a relatively large pledget of absorbablesponge material to be compressed and inserted into the biopsy tract in ahydrated state. The absorbable sponge material for use in facilitatinghemostasis may be any absorbable sponge which is capable of deformingupon hydration to be delivered by fluid pressure through a biopsy needleor other cannula.

Prior to discussing the present invention in further detail, thefollowing terms are defined:

“Pledget” means a piece of absorbable sponge of a generally elongatedshape having a size which allows injection in a hydrated state through abiopsy needle or other cannula.

“Sponge” means a biocompatible material which is capable of beinghydrated and is resiliently compressible in a hydrated state.Preferably, the sponge is non-immunogenic and may be absorbable ornon-absorbable.

“Absorbable sponge” means sponge which when implanted within a human orother mammalian body is absorbed by the body.

“Hydrate” means to partially or fully saturate with a fluid, such as,saline, water, contrast agent, thrombin, therapeutic agent, or the like.

“Kneading” of the absorbable sponge material means both dry and wetmanipulation of sponge material which compresses, enlarges, or changesthe shape of the sponge material causing the sponge material to haveimproved expansion response.

FIG. 1 illustrates one example of a punch 10, also called a dye cutter,for cutting an absorbable sponge sheet 20 into pledgets 18 of anappropriate size for delivery to a biopsy tract. The punch 10 includes arectangular blade 22 fixed to a plate 24 having a handle 26. The punch10 is pressed down onto a flat sheet 20 of commercially availableabsorbable sponge to cut the pledget 18 of an appropriate size. Inaddition to the punch 10 illustrated in FIG. 1 other cutting devices,such as, a scissor type hand punch, an automatic punching machine, or atemplet and knife may be used for preparation of the pledget 18. Analternative pledget forming system will be discussed in further detailbelow with respect to FIGS. 11-13.

FIG. 2 shows the adaptor 12 according to the present invention in whichthe pledget 18 is placed for hydration and for delivery through thebiopsy needle 16. The adaptor 12 allows pieces of absorbable spongematerial with relatively large cross sections to be easily deliveredthrough a biopsy needle 16 with a much smaller cross section. Theadaptor 12 also functions to remove air from the pledget 18.

The adaptor 12 which delivers the hydrated pledget 18 to the needle 16includes a first end 30 having an annular lip 32 or female luer fittingfor connection to the syringe 14. A second end 34 of the adaptor 12 hasa male luer fitting 36 for connection to a biopsy needle 16 or othercannula. The luer fitting 36 includes a tapered external surface 38 anda retaining ring 40 with internal threads for receiving an annular lipof the biopsy needle. The adaptor 12 has an internal lumen with a firstdiameter D₁ at the first end 30 and a second diameter D₂ at the secondend 34. Between the first and second ends of the adaptor 12 a taperedsection 42 of the adaptor provides a funnel for compressing the hydratedpledget 18 prior to injection through the biopsy needle 16 and needlehub 28.

The adaptor 12 may be formed in any known manner such as by molding froma plastic material. Preferably, the adaptor 12 is transparent so thatthe pledget 18 can be viewed through the adaptor and the user canvisually monitor when the pledget is loaded within the adaptor and whenthe pledget has been delivered into the needle. The adaptor lumen may beprovided with a friction reducing coating for improved delivery. Thedelivery fluid also reduces friction for improved delivery by wettingthe exterior surface of the pledget 18.

The syringe 14 includes a male luer fitting 46, a fluid chamber 48, anda plunger 50. The first end 30 of the adaptor 12 is connectable to theluer fitting 46 of the conventional syringe 14. The syringe 14 may beprovided with a spring 52 for automatic filling of the syringe 14 with apredetermined volume of fluid. Alternatively, the syringe may include athreaded syringe plunger, as shown in FIG. 7, for accurate injection ofsmall quantities of fluid. The syringe volume will vary depending on theamount of fluid needed for hydration and delivery of the pledget 18through the biopsy needle 16.

A biopsy needle 16 for use with the present invention is preferably aco-axial biopsy needle, such as a bi-axial or a tri-axial biopsy needle.A co-axial biopsy needle includes an outer needle or cannula throughwhich a tissue sample is removed with a tissue scoop or other biopsyinstrument. Once the tissue sample has been removed, the outer cannularemains in the patient as illustrated in FIG. 6. Although the cannulafor delivery of the sponge pledget has been described as a biopsyneedle, the cannula may be a catheter, sheath, or any other type ofcannula.

A preferred method of facilitating hemostasis of a biopsy tract will bedescribed with reference to FIG. 4 which shows the loading and hydrationof the pledget 18 within the adaptor 12. A pledget 18 is cut asdescribed above and placed within the adaptor 12 from the first end 30of the adaptor. The syringe 14 is filled with a predetermined amount offluid, such as saline, and is connected to the first end 30 of theadaptor 12 by the luer fitting 46. The plunger 50 of the syringe 14 isthen depressed slowly causing fluid to pass into the adaptor 12,hydrating the pledget 18, and filling the adaptor with a column offluid. Care should be taken to inject the fluid slowly to prevent thepledget from being ejected out of the second end 34 of the adaptor.Preferably, the user waits a few seconds once the fluid is injected intothe adaptor 12 until the pledget 18 is adequately hydrated creating alubricous surface on the pledget. The pledget 18 may expand within theadaptor to fill or nearly fill the lumen of the adaptor. The adaptor 12with the pledget 18 hydrated within the proximal end is ready to injectthe pledget into a biopsy tract to facilitate hemostasis within thebiopsy tract. The adaptor 12 may be loaded prior to beginning the biopsyprocedure.

After the biopsy procedure has been completed, the outer sheath of thebiopsy needle 16 through which the biopsy has been taken is maintainedin place within the biopsy tract, as shown in FIG. 6. The biopsy needle16 provides pre-established targeting of the delivery site for deliveryof the absorbable sponge pledget 18 and eliminates the uncertainty ofre-access. The luer fitting 36 of the adaptor 12 is connected to thebiopsy needle hub 28, as illustrated in FIG. 6. The biopsy needle 16 iswithdrawn a short distance, such as about 1 to 20 mm, along the biopsytract to provide space for the pledget 18 to be received in the biopsytract. Additional fluid is then rapidly injected by the syringe to movethe pledget 18 into the biopsy needle 16. When the adaptor lumen hasbeen blocked by the hydrated pledget 18 which has swelled within theadaptor, injection of additional fluid will push the pledget through thetapered section 42 of the adaptor. If the adaptor lumen has not beenentirely blocked by the pledget 18, the venturi effect will help drawthe pledget through the tapered section 42 of the adaptor. After thepledget 18 is moved to the biopsy needle 16, the pledget 18 is thendelivered from the needle 16 to the biopsy tract by rapid injection ofadditional fluid by the syringe 14. The hydrated pledget 18 quicklyexpands upon delivery to fill the available space in the biopsy tract tofacilitate hemostasis and provide localized compression.

As illustrated in the cross sectional view of FIG. 7, one example of aneedle hub 28 has an interior diameter D₃ which is larger than thediameter D₂ at the distal end 36 of the adaptor 12. The large internaldiameter needle hub 28 allows the hydrated pledget 18 which has beencompressed by the tapered section 42 of the adaptor to expand in theneedle hub before being compressed again into the needle lumen. Thiscompression and enlargement of the hydrated absorbable sponge material,does not adversely effect the pledget delivery and in fact improves theexpansion response of some delivered sponge materials as will bediscussed in further detail below.

A smooth tapered transition between the lumen of the needle hub 28 andthe needle lumen helps to provide for easy injection of the pledget 18.However, needles having internal steps between the needle hub 28 and theneedle 16 have been used and the pledget 18 is still injectedsuccessfully. According to an alternative embodiment of the invention,the needle hub 28 may be designed to have a inner diameter approximatelythe same as the inner diameter D₂ at the distal end 36 of the adaptor.

Preferably, specific measured doses of fluid are used to achieve each ofthe steps of the treatment procedure depending on the pledget size andthe dimensions of the adaptor 12, the needle 16, and the needle hub 28.The pledget 18 should be completely delivered into the biopsy tract bythe fluid and only a minimal amount of extraneous fluid should bedelivered. For example, the pledget 18, once inside the needle, may bedelivered with about 0.02 to 1.5 ml of fluid depending on the size ofthe needle 16 used. Injection of larger amounts of fluid may distend thebiopsy tract or displace the pledget within the organ.

According to one example, a pledget 18 having a size of approximately 20mm by 2 mm cut from a sheet of commercially available Gelfoam having athickness of approximately 1.5 mm can be hydrated and injected through astandard 18 gauge, approximately 15 cm long biopsy needle withapproximately 0.9 ml of fluid. An adaptor according to this example hasa first diameter D₁ of about 0.38 cm, a second diameter D₂ of about 0.14cm, a total length of about 3.80 cm, and a taper angle of about 45°.About 0.3 ml of fluid is injected slowly to hydrate the pledget 18 andfill the adaptor with a column of fluid. Approximately 0.3 ml of fluidis then injected to load the pledget 18 from the adaptor 12 into thebiopsy needle 16. Finally, about 0.3 ml of fluid is injected to deliverthe pledget 18 into the biopsy tract. Loading of the pledget from theadaptor 12 into the needle 16 and delivery from the needle to the biopsytract can be combined in one step by delivery of approximately 0.6 ml.Accurate and complete injection of the pledget with a minimum amount ofextraneous fluid is achieved by this volumetric injection technique.

According to an alternative embodiment of the adaptor illustrated inFIG. 4, vent holes 44 extend through the side walls of the adapter 12adjacent the second end 34 for venting fluid during loading of thepledget 18. As illustrated in FIG. 5, the user places a finger over thesecond end 34 of the adaptor 12 to prevent the pledget from exiting theadaptor. The plunger 50 of the syringe 14 is then depressed slowlycausing fluid to pass into the adaptor 12 and hydrate the pledget.Preferably, the user waits a few seconds once the fluid is injected intothe adaptor 12 until the pledget 18 is hydrated. Once the pledget 18 ishydrated, additional fluid is then injected quickly into the adaptor 12to move the pledget 18 from the first end 30 of the adaptor towards thesecond end 34 of the adaptor. As the pledget 18 is compressed by thetapered section 42 of the adaptor 12 air and fluid are allowed to escapefrom the adaptor through the vent holes 44. Once the pledget 18 has beenmoved into the position illustrated in FIG. 5 adjacent the second end34, fluid injection is halted. The adaptor 12 with the hydrated pledget18 within the distal end is ready to insert the pledget through a biopsyneedle to facilitate hemostasis within the biopsy tract.

As an alternative to placement of a finger at the distal end of theadaptor 12 during advancement of the pledget 18 through the taperedsection 42, a removable cap may be used. Further, the vent holes 44 maybe omitted and a screen or a cap having a screen may be used to allowfluid to pass through the screen while the screen prevents the pledget18 from being ejected. One example of a vent cap will be described infurther detail below with respect to FIGS. 14 and 15.

An alternative embodiment of the delivery system is illustrated in FIG.7 in which an adaptor 12 is provided with a pressure indicator 64 tomonitor pledget injection. Preferably, the pressure indicator 64 isremovably attached at a luer fitting 66 provided on a side of theadaptor 12. The pressure indicator 64 includes a pressure dome 68movable from the convex shaped extended position illustrated in FIG. 7to a flat position depending on the pressure inside the adaptor 12.Internal pressure within the biopsy needle 16, the adaptor 12, and thesyringe 14 will drop as the pledget 18 is extruded from the biopsyneedle into the biopsy tract. This causes the pressure dome 68 to movefrom the convex position illustrated in FIG. 7 to a flat position,indicating that pledget delivery is complete.

FIG. 8 illustrates an alternative embodiment of an adaptor 12 a in whichthe tapered section 42 a is shorter and more abrupt. The particular sizeand shape of the adaptor 12 a according to either FIG. 2 or FIG. 8 mayvary depending on the size of biopsy needle, the tissue sample size, andthe size of pledget to be delivered. One example of the adaptor 12 a ofFIG. 8 for delivery of an absorbable sponge pledget 18 through anapproximately 18 gauge biopsy needle has a first adaptor diameter D₁ ofabout 0.25 cm or greater, preferably about 0.30 to 0.80 cm and a secondadaptor diameter D₂ of about 0.25 cm or less, preferably, about 0.05 to0.23 cm. An angle made by a wall of the tapered section 42 a with alongitudinal axis of the adaptor 12 a may vary from about 5° to 90°, butis preferably between about 30° and 60°. The tapered section 42 a isillustrated with a substantially planar interior surface, when shown incross section. However, the tapered section 42 a may also have a convexor concave surface in cross section. The dimensions described for theadaptor 12 a are appropriate for use with an approximately 18 gaugebiopsy needle commonly used for liver biopsies. For some of the muchlarger biopsy needles or cannulas used for skin or breast biopsies theadaptor dimensions would be scaled up accordingly.

FIG. 8 also shows a connector 70 for connecting the adaptor 12 to asyringe 14 when the proximal end of the adaptor is larger in diameterthan the standard syringe fitting. The connector 70 includes a first end72 for connection to the syringe 14 and a second end 74 for connectionto the adaptor 12.

One type of absorbable sponge material which is acceptable for use inthe present invention is Gelfoam, manufactured by the Upjohn Company.Gelfoam is a porous, pliable, cross-linked gelatin material and isavailable commercially in sheet form as pre-compressed or non-compressedsponge. The material may be provided preformed as a pledget 18 or may becut with a punch 10, or a stencil or template and knife to form apledget as described above. Once hydrated, the pledget 18 can be easilycompressed to fit into a lumen having a smaller cross sectional areathan the original cross sectional area of the pledget. Additionally, thekneading of the hydrated pledget 18 during delivery encourages airtrapped within the Gelfoam to be expelled and replaced with fluid,allowing rapid expansion upon delivery. When a pledget 18 of apre-compressed Gelfoam is hydrated and kneaded (expelling air) duringdelivery, the pledget will have the absorbtion capacity to rapidlyexpand to many times (e.g., 3 or more times) its original dry volumeupon delivery. When a pledget 18 of the non-compressed Gelfoam ishydrated and kneaded (expelling air) during delivery, the pledget willhave the absorbtion capacity to rapidly expand to its original dryvolume upon delivery. These properties make the Gelfoam sponge materialparticularly useful for facilitating hemostasis of biopsy sites.

Abrupt lumen diameter changes within or between the adaptor 12 or theneedle 16 will improve “kneading” of the absorbable sponge materialimproving hydration of the absorbable sponge material thereby improvingthe expansion properties of the hydrated delivered absorbable sponge.According to the alternative embodiments of the adaptor illustrated inFIGS. 9 and 10, enlarged, recessed, or irregular areas in the lumen ofthe adaptor are provided to impart additional kneading action to theabsorbable sponge material further improving expansion properties of thesponge.

The adaptor 12 b of FIG. 9 includes two enlarged areas 72 of the lumen.As the absorbable sponge pledget 18 passes through the lumen of theadaptor 12 b the material expands and is compressed by the adaptor toincrease kneading of the pledget. FIG. 10 illustrates anotheralternative embodiment of the adaptor 12 c including a lumen with aplurality of staggered irregularities 74 for improved kneading of theabsorbable sponge pledget 18. The irregularities 74 will preferably havea relatively smooth surface to prevent the absorbable sponge materialfrom becoming caught on the irregularities.

FIG. 11 illustrates an alternative embodiment of an adaptor 112 with apledget formation template 122 attached to the adaptor. As shown in FIG.11, the adaptor 112 includes a proximal end 130 having a female luer 132and a distal end 134 having a male luer 136. The pledget 118 is insertedin the proximal end 130. A tapered section 142 is provided within theadaptor 112 for compressing the pledget 118 into the biopsy needle.

When delivering a pledget 118 of absorbable sponge material, it isimportant to deliver a desired amount of the sponge material using aminimum amount of fluid. Some devices and methods which allow thedelivery of sponge material with a minimum amount of fluid include theuse of the pledget configuration illustrated in FIG. 11, the use of avent cap for staging of the pledget as illustrated in FIGS. 14 and 15,and the withdrawal of the biopsy needle during delivery as illustratedin FIG. 16.

Pledgets 118 having increased proximal cross sectional areas are moreeasily delivered than pledgets with constant cross sectional areas ordecreased proximal cross sectional areas. FIG. 11 illustrates a pledget118 having a proximal cross sectional area which is approximately twiceits distal cross sectional area. The smaller material mass at the distalend of the pledget 188 increases the ease of inserting the pledget intothe adaptor 112. The smaller distal end of the pledget also passesthrough the delivery cannula or biopsy needle without creating a largeback pressure to resist the delivery of the pledget through the cannula.The larger proximal section of the pledget 118 provides a better sealwithin the interior of the adaptor 112 and the cannula 16 which allows aminimum amount of fluid to be used to advance the pledget. The increasedmaterial at the proximal end of the pledget 118 also increases theamount of sponge material delivered to the biopsy tract.

Pledgets 118 with increased cross sectional area proximal ends may beprepared in a variety of manners. For example, if a pledget 118 isprepared from a sheet of sponge material, the increased proximal masscan be achieved by cutting the pledget with an enlarged proximal end.Alternatively, the pledget 118 may be formed by folding, rolling,compressing, or otherwise manipulating the sponge material to thedesired shape. The proximal pledget mass may also be increased by addingseparate pieces of material to the proximal end of the pledget. Thisadditional material may be layered, wrapped, coiled or attached to thepledget in any other manner. The pledgets may also be formed by molding,bump extruding, dipping, or the like. The larger cross sectional areaproximal end is generally about 1.2 to 4 times the cross sectional areaof the distal end. In addition, the proximal end with the larger crosssection area preferably extends along about ⅛ to ¾ of the total pledgetlength.

The pledget 118 illustrated in FIG. 11 has been formed by cutting astrip of material from an absorbable sponge sheet 20 with the aid of thetemplate 122 as illustrated in FIG. 13. After the strip is cut, theproximal end of the strip is then folded back onto itself to form apledget 118 with an increased cross sectional area and material mass ata proximal end. One example of a preferred embodiment of a Gelfoampledget for delivery down a 20 gauge biopsy needle or cannula has a sizeof approximately 0.1×1.5×0.06 inches and is folded as illustrated inFIG. 11 to an overall length of about 0.9 inches. Placing this pledget118 in an adaptor 112 having a largest internal diameter of 0.125 inchesallows the pledget to be delivered to a 20 gauge or larger biopsyneedle. Other common biopsy procedures use an 18 gauge or larger biopsyneedle through a slightly larger guide cannula and would receive asomewhat larger pledget. After taking a core sample and removing thebiopsy needle from the cannula guide, a pledget 118 maybe deliveredthrough the cannula to the biopsy site. The pledget 118 for use in thesystem employing an 18 gauge or larger biopsy needle may be formed froma strip which is approximately 0.11-0.12 inches wide by about 3.125inches long with a thickness of about 0.06 inches and folded to anoverall length of about 2.2 inches. This pledget having a singlethickness distal end and double thickness proximal end can De deliveredfrom an adaptor having a largest internal diameter of approximately0.125 inches.

One method for forming the pledget 118 with the enlarged proximal endwith the aid of a template 122 is illustrated in FIG. 13. The template122 is a flat plate having recesses 124 along one or more edges of thetemplate. The recesses 124 have a width and a length which correspondsto a preferred width and length of the pledget. The recesses 124 form araised bar 126 at a location where the pledget should be folded. Whenthe template is pressed onto a sheet 20 of absorbable sponge material,the bar 126 makes an indentation or groove in the sponge material. Auser cuts along the side 128 and end 129 edges of the template 122 witha blade to form a strip of the sponge material which is then foldedalong the groove or crease formed by the bar 126 to form the pledget118. It is important to securely hold the sponge sheet by applyingdownward pressure to the template 122 during cutting to prevent tearingand breaking of the sponge material. Prior to folding the strip ofsponge material to form the pledget, the strip may be compressed with aflat surface of the template to compact the sponge and assist in loadingthe pledget into the adaptor 112.

Although the template 122 has been illustrated as a plate which isattached to the adaptor 112, it should be understood that the templatecan also be a separate member. In addition, the template 122 may provideguides for forming pledgets of different sizes for delivery throughdifferent sized biopsy needles. The template 122 may be provided with orwithout the creasing bar 126 and may be transparent or opaque. In theopaque version, the edges of the recesses 124 are used to align thetemplate with an edge of the sponge sheet 20. In contrast, in atransparent version of the template, the recesses 124 may be eliminatedand a visual indication or line may be provided which assists inaligning an edge of the sponge sheet with the template.

FIGS. 14 and 15 illustrate a preferred vent cap 70 for use with theadapter 112. As discussed above with respect to FIG. 5, vents maybe usedto assist in hydrating and staging the pledget within the adapter. Inparticular, vents will allow the pledget to be moved to a preferredaxial location within the adapter 112 prior to delivery. In addition,the vents allow fluid to be injected and air to be removed from thepledget prior to delivery. The vent cap 70 as illustrated in FIG. 14includes a female luer connector 72 including a flange 74 which isreceived on the male luer 136 of the adapter 112. The vent cap 70 alsoincludes a conical portion 76 which is configured to extend into adistal end 134 of the adaptor 112. The conical portion 76 has one ormore fluid paths or vent holes 78 which allow air and fluid to exitthrough the vent cap but prevent the absorbable sponge material of thepledget 118 from passing through the vent cap. The vent hole mayalternatively be positioned between the vent cap 70 and the adapter 112.Preferably, an exterior of the conical portion 76 forms a seal with thelumen of the adaptor 112 at the distal end. The diameter of the venthole 78 is approximately 0.005-0.02 inches, preferably approximately0.01 inches. This small vent hole 78 allows the purging and venting offluid and air from the adapter 112 but does not allow the pledget 118 topass through the venthole, even at high pressures such as 5 psi orgreater. The use of the vent cap 70 allows the user to apply highpressures with the syringe used to hydrate the pledget The highpressures drive the fluid into the pledget causing rapid and thoroughhydration of the sponge material. Repeated pulsing of the fluid with thesyringe will provide more complete hydration of the pledget.

The vent cap 70 also positions the pledget 118 at a preferred axialposition just proximal to the distal end 134 of the adapter 112 asillustrated in FIG. 15. This positioning of the pledget 118 away fromthe end of the adaptor prevents the pledget from becoming trappedbetween the adaptor 112 and the biopsy needle hub 28 which is attachedto the distal end of the adaptor. In addition, after hydration of thepledget and removal of the vent cap 70 the sponge material may tend toswell out of the distal end of the adapter 112. Accordingly, the conicalportion 76 of the vent cap 70 preferably extends into the adaptor 112approximately 0.01 to 0.1 inches, more preferably about 0.01 to 0.03inches.

According to the present invention, the portion of the vent cap 70 whichextends into the lumen of the adaptor 112 can be any desired shape suchas dome-shaped, cylindrical, conical or other shape.

As described above, the pledget maybe delivered to the biopsy tract byholding the biopsy needle or cannula 16 stationary and injecting thepledget through the biopsy needle. If additional pledgets are to bedelivered, the biopsy needle 16 is withdrawn a distance sufficient toaccommodate an additional pledget and the additional pledget is theninjected.

According to an alternative embodiment of the invention, the method ofdelivering the pledget into the biopsy tract may include withdrawing thebiopsy needle or cannula 16 during delivery of the pledget 18 to deliverthe pledget in an elongated trail which follows the biopsy tract.Placing the absorbable sponge material in a tril which fills the entirebiopsy tract provides the added benefit of providing hemostasis alongthe entire biopsy tract. This is particularly helpful for stopping thebleeding of biopsy tracts in organs which tend to have excessivebleeding such as the liver, kidney, spleen, and other vascular organs.

In order to achieve a trail of absorbable sponge material in the biopsytract, one method of the present invention involves the delivery of thepledget into the biopsy needle by a predetermined amount of fluid. Thebiopsy needle is then withdrawn at a velocity V while the pledgetmaterial is ejected from the biopsy needle at a velocity E with respectto the biopsy needle. The velocity V at which the biopsy needle iswithdrawn is equal to or less than the velocity E at which theabsorbable sponge material is delivered. The control of injection offluid and withdrawal of the needle to achieve the desired trail ofabsorbable sponge material in the biopsy tract maybe controlled with aninjection controlling device.

According to an alternative embodiment of the invention illustrated inFIG. 16, the adaptor maybe used to deliver the pledget into the biopsyneedle 16 and then the adaptor is removed from the biopsy needle. Aplunger or stylet 80 which is generally provided with the biopsy needle16 for inserting the biopsy needle is then used to deliver the pledgetfrom the biopsy needle. As shown in FIG. 16, the biopsy needle extendsthrough the tissue 84 and into the organ 86 for removal of a core oftissue. After biopsy, the pledget is injected into the needle 16 and theplunger 80 is placed within the biopsy needle so that a distal end ofthe plunger abuts the proximal end of the pledget 118. The plunger 80 isthen held stationary while the biopsy needle 16 is withdrawn from thebiopsy site. The plunger 80 causes the pledget 118 to be delivered in atrail 88 which fills the biopsy tract. The trail 88 preferably extendsalong the entire biopsy tract to or past a surface of the organ 86. Thedelivery of the trail 88 of absorbable sponge material provides anadvantage over the delivery of discrete blobs of material because thetrail is able to provide hemostasis along the entire tract. In contrast,if a blob of absorbable sponge material is delivered within the tract ata depth of 1-2 cm from the surface of the organs, this 1-2 cm of biopsytract may continue to bleed significantly.

As an alternative to delivery of the pledget as a trail, the pledget maybe delivered as a plug. To deliver a plug the plunger 80 is advancedinto the needle 16 pushing the pledget out of the distal end of theneedle while the needle is held stationary. A combination of delivery ofplugs and trails may also be used. The pledget material may be deliveredentirely within a single anatomical structure or may cross two or moreanatomical structures such as an organ, surrounding tissue and faciallayer.

Although the invention is primarily intended for delivery of absorbablesponge, non-absorbable sponge may also be delivered with the devices,systems, and methods of the present invention. A non-absorbable spongemay be desirable where it will be necessary to locate the biopsy site ortract after the procedure.

Although the pledget 18 has been shown and described as having arectangular cross section, pledgets of other shapes may also be used.For example, the pledget may be preformed in any shape, such as with arectangular or circular cross section or may be rolled from a thin sheetof absorbable sponge material. The pledget 18 may have a multi-sidedcross section, a star shaped cross section, or a folded cross sectionand may have through or blind holes formed in the dry pledget. Inaddition, the pledget size and shape can be matched to the size andshape of a particular delivery site. Pledget shapes having greatersurface area provided by features such as fins provide faster hydration.

The continuous structure of the absorbable sponge pledget 18 providesmore secure and reliable placement than a paste or liquid and can evenfacilitate partial withdrawal, removal, or movement of the deliveredpledget.

In some instances it may be desirable to deliver multiple pledgets inspaced apart positions along the biopsy tract, particularly for a longbiopsy tract. For delivery of additional pledgets, the biopsy needle 16is retracted a distance sufficient to provide a space to accommodate anadditional pledget 18 and the injection procedure described above isrepeated for the additional pledget(s). For a particularly large biopsysite or cavity, additional pledgets 18 may be injected beside aninitially injected pledget until the cavity is filled.

Although biopsy is most commonly performed by biopsy needle, biopsy mayalso be performed through other cannulas, such as catheters, longneedles, endoscopes, or the like. The treatment procedure according tothe present invention can be used for facilitating hemostasis ofpuncture wounds through different types of cannulas including needles,catheters, endoscopes, and the like. In addition, the treatmentprocedure and systems according to the present invention may be used todeliver absorbable or non-absorbable sponge for other therapys. Forexample, sponge may be delivered for cosmetic or reconstructive bulkingor for temporary or permanent intravascular embolization.

The absorbable sponge pledget 18 may be used to deliver a beneficialagent, such as contrast agent, thrombin, radiation treatment, or thelike. The pledget can also be used to deliver therapeutic agents, suchas radioactive isotopes for localized treatment of tumors, anti-canceragents, anti-metastatic agents, and the like. Examples of anti-canceragents include 5-fluorouracil, cisplatin, prednisone, and othersdescribed in U.S. Pat. No. 4,619,913 which is incorporated herein byreference. The absorbable sponge pledget 18 may be presoaked with thebeneficial agent for delivery to the biopsy tract. Alternatively, thepledget 18 may be hydrated with the beneficial liquid agent or the agentmay be delivered to the pledget after the pledget is placed within thebiopsy tract.

A pledget formed of commercially available Gelfoam material will beabsorbed by the body within 1 to 6 weeks. However, the pledget materialmay be designed to provide different rates of absorption. For example,Gelfoam can be designed to be absorbed at different rates by varying thedegree of cross-inking. Preferably, the pledget is designed to beabsorbed in less than one month.

The treatment of a biopsy tract with a hydrated and injected pledget 18of absorbable sponge to facilitate hemostasis provides substantialadvantages in comfort over external pressure methods. In addition, thepresent invention also provides advantages over the insertion of anabsorbable sponge material in a dry state with an applicator. Inparticular, the adaptor 12 allows a relatively large pledget to becompressed and inserted into the biopsy tract in a hydrated state. Theinjected pledget 18 conforms in shape quickly to the shape of the biopsytract and immediately begins blocking blood flow. In contrast, a drypiece of sponge material must be cut to the particular size of thebiopsy tract and does not swell to fill the tract until the blood hassufficiently saturated the sponge material which can take significantlylonger and provides inadequate local compression.

While the invention has been described in detail with reference to thepreferred embodiments thereof, it will be apparent to one skilled in theart that various changes and modifications can be made and equivalentsemployed, without departing from the present invention.

What is claimed is:
 1. A method of preparing a sponge pledget fordelivery to a body to facilitate hemostasis, the method comprising:positioning a sponge pledget in an adaptor; covering a distal end of theadaptor with a vent cap which allows for venting fluid and preventsexpulsion of the pledget; and hydrating the sponge by injecting fluidinto the adaptor.
 2. The method of claim 1, wherein the pledget ispositioned in an adaptor which is substantially tubular.
 3. The methodof claim 1, wherein the vent cap positions a distal end of the sponge ata predetermined longitudinal position with respect to the adaptor. 4.The method of claim 3, wherein the predetermined longitudinal positionis proximal of the distal end of the adaptor.
 5. The method of claim 1,wherein the vent cap includes a conical portion configured to extendinto the distal end of the adaptor.
 6. The method of claim 5, whereinthe vent hole is provided at a tip of the conical portion.
 7. The methodof claim 1, further comprising delivering the hydrated sponge pledgetfrom the adaptor by removing the vent cap from the distal end of theadaptor and injecting additional fluid into the adaptor to deliver thepledget.
 8. The method of claim 1, wherein the sponge is hydrated byinjecting fluid at pressures of at least 5 psi.
 9. The method of claim1, wherein the sponge is hydrated by pulsing the injected fluid toprovide complete hydration.
 10. The method of claim 1, wherein thesponge is positioned in the adaptor in a dry state.
 11. A method ofpreparing a sponge pledget for delivery to a body to facilitatehemostasis, the method comprising: positioning a sponge pledget in anadaptor; covering a distal end of the adaptor with a vent cap whichallows for venting fluid and prevents expulsion of the pledget; andmoving the sponge pledget distally in the adaptor to a predeterminedposition by injecting fluid into the adaptor.
 12. The method of claim11, wherein the pledget is positioned in an adaptor which issubstantially tubular.
 13. The method of claim 11, wherein thepredetermined position is proximal of the distal end of the adaptor. 14.The method of claim 11, wherein the vent cap includes a conical portionconfigured to extend into the distal end of the adaptor.
 15. The methodof claim 14, wherein the vent hole is provided at a tip of the conicalportion.
 16. The method of claim 11, further comprising delivering thesponge pledget from the adaptor by removing the vent cap from the distalend of the adaptor and injecting additional fluid into the adaptor todeliver the pledget.
 17. The method of claim 11, wherein the sponge ispositioned by injecting fluid at pressures of at least 5 psi.
 18. Themethod of claim 11, wherein the sponge is positioned in the adaptor in adry state.